1. Field of the Invention
The present invention generally relates to a fuel injection system for use in an automotive vehicle and, more particularly, to the fuel injection system for injecting fuel into an automotive fuel intake system during the acceleration of an automotive engine.
2. Description of the Prior Art
It is generally well known that the fuel injection system in an automotive vehicle is designed to inject fuel in a quantity appropriate to the amount of air introduced into a combustion chamber of, for example, an internal combustion engine. During a transit period such as, for example, during the acceleration of the combustion engine, however, it has often been observed that, due to a delay in detecting the amount of air being supplied through the automotive intake system and/or a substantial time required for the fuel injected into the automotive intake system to be actually introduced into the combustion chamber, the ratio of air relative to fuel, hereinafter referred to as an air-to-fuel ratio, of a combustible air-fuel mixture cannot be maintained at an optimum value. Therefore, it is a recommended practice to increase the amount of fuel to be injected into the automotive intake system once acceleration has been detected.
In order that the amount of fuel to be injected can be increased upon the detection of an occurrence of acceleration, it is a generally employed practice to utilize, as a means for detecting the acceleration, a throttle sensor for detecting the opening of a throttle valve disposed in the automotive intake system and for generating an output signal indicative of the opening of the throttle valve at intervals of a predetermined time. According to this conventional practice, the detection of the occurrence of the acceleration is made when the amount of change in the level of the output signal generated from the throttle sensor at intervals of the predetermined time exceeds over a predetermined value, so that an asynchronous injection of fuel into the fuel intake system and then into the combustion chamber can be effected.
The prior art fuel injection system which operates in the above-described manner requires the use of a throttle sensor for the detection of the occurrence of acceleratiom, resulting in an increase in the manufacturing costs of the system.